
\prefacesection{Acknowledgments}
%\section*{Acknowledgments}

My greatest debt is to Davide Sangiorgi.
%I do not forget that Davide suggested the possibility of doing a PhD with him 
%in Bologna
%when I was only looking for an internship.
Having him as supervisor has been truly inspiring.
His careful supervision has influenced enormously my way of doing (and approaching) research.
His continuous support and patience 
during these three years
were fundamental to me.
I am still amazed by the fact that Davide had always time for me, 
not only for scientific discussions but also for sorting out everyday issues. 
I am most grateful to him for his honest and direct advice, 
and for the liberty that he gave me during my studies. 

I also owe much to Camilo Rueda and Frank D. Valencia.
I do not forget that it was Camilo who introduced me to research, thus 
giving me an opportunity that most people in his position would have refused.
Even if my PhD studies were not directly related to his research interests,
Camilo was always there, interested in my progresses, encouraging me with his support and friendship.
Frank not only introduced me to concurrency theory; 
he also gave me constant advise and support during my PhD studies and long before.
Frank %'s career was (and still is) a constant source of inspiration and reference to me. 
%Also, he 
had a lot to do with me coming to Bologna, and that I will never forget. 
%Thanks to both of you for the faith you have had in me.

% As surprising as he might find it, Daniele Varacca
% has a lot to do with me completing my PhD.
% I met Daniele in 2005, when I was rather confused about the idea of doing a PhD abroad. 
% The experience of interacting with him at that time, 
% and the opportunity of 
% observing his way of understanding and approaching theoretical research, 
% marked me in a profound way.
% I have been fortunate to count with his support and honest advice along these years.

There is no way in which I could have completed this dissertation by myself.
It has been a pleasure to collaborate with extremely talented people, to whom 
I am deeply grateful: Cinzia Di Giusto,
Ivan Lanese,
Alan Schmitt,
Gianluigi Zavattaro. 
Thank you for your 
%I have learned many things from each of them; I am deeply grateful 
%for their 
kindness, generosity and, above all, for your patience.

Many thanks to Uwe Nestmann and Nobuko Yoshida for having accepted to review this dissertation.
%They were very kind in providing insightful comments in a very short amount of time.
Thanks also to the members of my internal committee (\emph{commissione}), Cosimo Laneve and Claudio Sacerdoti-Coen.
I am indebted to Simone Martini, the coordinator of the PhD program, 
for all his constant availability and kindness.

Many people proof-read parts of this dissertation, and provided me 
with constructive criticisms. I am grateful to all of them for their time and availability: 
Jes\'{u}s Aranda,
Alberto Delgado,
Cinzia Di Giusto,
Daniele Gorla,
Juli\'{a}n Guti\'{e}rrez,
Hugo A. L\'{o}pez,
Claudio Mezzina,
Margarida Piriquito,
Frank D. Valencia. 
A special thanks goes to 
Daniele Varacca, who suffered an early draft of the whole document and provided me with insightful remarks. 
Along these years I have benefited a lot from discussions with/comments from a lot of people.
I am most grateful for their positive attitude towards my work:
Jes\'{u}s Aranda,
Ahmed Bouajjani, 
G\'{e}rard Boudol,
Santiago Cort\'{e}s, 
Rocco De Nicola,
Daniele Gorla,
Matthew Hennessy,
Thomas Hildebrandt,
Kohei Honda,
Roland Meyer,
Fabrizio Montesi,
Camilo Rueda,
Jean-Bernard Stefani,
Frank D. Valencia,
Daniele Varacca,
Nobuko Yoshida.


During 2009 I spent some months visiting Alan Schmitt in the SARDES team at INRIA Grenoble - Rh\^{o}ne-Alpes.
The period in Grenoble was very enriching and productive; 
a substantial part of this dissertation was written there.
I am grateful to Alan and to Jean-Bernard Stefani for the opportunity of working with them
and for treating me as another member of the team. 
I would like to thank Diane Courtiol for her patient help
with all the administrative issues during my stay, 
and to Claudio Mezzina (or the ``tiny little Italian with a pony tail'', as he requested to be acknowledged) 
for being such a friendly office mate. 
I also thank the INRIA Equipe Associ\'{e}e BACON %(Behavioral Analysis of COmpoNent-based distributed systems)
for partially supporting my visit.


I would like to express my appreciation to the University of Bologna - MIUR
for supporting my studies through a full scholarship.
Thanks also to
the administrative staff in the Department of Computer Science, 
for their help and kindness in everyday issues.

%for making it possible creating such an opportunity to foreign students. 
%for being so welcoming and kind to me. 
%A first thought goes to , in particular to Vito Cainazzo and Laura Mezzeti.


%Friends:

I am most proud to be part of a small group of Colombians doing research abroad.
We all 
share many things:
we started in the same research group, % in Colombia,  
have similar backgrounds, and came to Europe more or less at the same time.
With most of them I even shared an office for a long time. %and had great times. 
Many thanks to: 
Jes\'{u}s Aranda, for his inherent kindness;
Alejandro Arbelaez, for the good times while working in Colombia and his hospitality during trips to Paris;
Andr\'{e}s Aristiz\'{a}bal, for the constant support in spite of our favorite football teams;
Alberto Delgado,  with whom I started doing research back in 2002 and has always been there ever since;
Gustavo Guti\'{e}rrez,  for the old, good times when he was my first boss, and for the sincere support during all these years;
Julian Guti\'{e}rrez, for all the discussions on life and research, during our PhDs and even way before;
Hugo A. L\'{o}pez, for sharing with me  the experience of living in Italy, 
 several trips,  and a plenty of discussions on concurrency theory and life at large; 
Carlos Olarte, for all the good times in Paris and hospitality in the great city of Bourg-la-Reine;
Luis O. Quesada, for 
his exceptional kindness and hospitality 
during a visit to Ireland (despite of the fact that my visit brought historical floodings to the Cork region).
Above all, I would like to thank all of them for being my friends. %their friendship, constant support, and patience.

% A special thanks goes to Alberto Delgado, 
% with whom I started doing research back in 2002 
% and has always been there ever since,
% and to Hugo A. L\'{o}pez, 
% with whom I have shared manay things: 
% the experience of living in Italy, 
% several trips, 
% and a plenty of discussions on concurrency theory and life at large. 




Perhaps the most significant achievement of my PhD studies is all the people I have meet along the way.
A special thanks goes to: Cinzia Di Giusto, 
for her constant support and friendship, and for being the most enthusiastic partner in research one could imagine;
Antonio Vitale, for the several trips and for sharing with me bits of PhD frustration and pizzas of varying quality;
Ivan Lanese, the loyal friend, the reasonable flat mate, and the talented co-author.
Thanks also to:  
Stefano Arteconi, for insightful and enjoyable discussions on Italy, movies, and music;
Ferdinanda Camporesi, for the many chats and the movies we watched together;
Marco Di Felice, for being the most welcoming and friendly office mate in underground and being worse than me in \emph{calcetto};
Ebbe Elsborg (and family) ---the most loyal reader of my blog--- for 
his kind hospitality during 
%several dinners at his place in Bologna, 
the most splendid vacation in Denmark I could have imagined, 
%for being the , 
and for plenty of discussions on pretty much every aspect of life;
Elena Giachino and Luis P\'{e}rez, for all the fun we had together at summer schools, and for dinners and parties at Pisa;
Zeynep Kiziltan, for the chats over lunch that \emph{didn't deal} about work;
Flavio S. Mendes, for the many trips we did together around Italy, the constant support and friendship, and the many times I stayed at his place;
Margarida Piriquito, for the most unexpected friendship I can remember;
Sylvain Pradalier, or the coolest French guy I could have shared an office with;  
Alan Schmitt (and family), for the several great dinners at his place (in Grenoble, but also in Casalecchio)
and the clever games in which I would always lose no matter how hard I would try. 
%where 

Last but not least, I would like to thank my family for their unconditional, constant support.
There are no words to thank my parents, my sisters, my brother, and my grandmother.
Their love gave me strength to overcome the difficult times.
I would also like to thank Andr\'{e}s F. Monsalve, who is more like a brother than a friend to me.
Thanks also to the rest of my family, 
the many cousins, uncles, and aunts for their continued support towards me. 





